Comparator for collocating a cutter in a boring bar



E. A. ARP.

Jan. 20, 1953 COMPARATOR FOR COLLOCATING A CUTTER IN A BORING BAR Filed June 10, 1948 4 Shea s-Sheet 1 at on F.

E M N mi M A 0. am w. E E

COMPARATOR FOR COLLOCATING A CUTTER IN A BORING BAR Filed June 10, 1948 E. A. ARP

Jan. 20, 1953 4 Sheets-Sheet 2 ATTORNEY COMPARATOR FOR COLLOCATING A CUTTER IN A BORING BAR Filed June 10, 1948 E. A. ARP

Jan; 20, 1953 4 Sheets-Sheet 3 /NVE'/VTOR {WALD 4. 14/?! Patented Jan. 20, 1953 I COMPARATOR FOR COLLOCATING A CUTTER IN A BORING BAR Ewald A. Arp, Minneapolis, Minn, assignor to V Tobin-Arp Manufacturing Company, Minneapolis, Minn., a corporation of Minnesota Application June 10, 1948, Serial No. 32,231

This invention has relation to a comparator.

An object of the invention is to provide a new and improved apparatus adapted to be employed for the purpose of setting a cutting tool in a boring bar by comparison with or reference to a shaft to be capable of producing an internal bearing surface of diameter having direct relation to the diameter of said shaft.

A further object is to provide a new and improved comparator which will include a construction and arrangement for selectively receiving a shaft or a boring bar with cutting tool and an instrument capable of measuring and denoting the radius of each of said shaft and said borlng bar with cutting tool, the one with respect to the other, in such manner that the boring bar with cutting tool can be accurately set to have precisely the same radius as said shaft or to have any radius which may be predetermined, greater or less than the radius of said shaft.

A further object is to provide a new and improved comparator by employment of which the .setting of a cutting tool in a boring bar can be accomplished with great accuracy.

A further object is to provide a comparator wherein will be incorporated various desirable and improved features and characteristics novel both as individual entities of the comparator and in combination with each other.

And a further object is to provide a comparator which will be of construction and operative in the manner as hereinafter set forth.

With the above objects in view, as well as others which will appear as the specification proceeds, the invention comprises the construction, arrangement and combination of parts as now to be fully described and as hereinafter to be specifically claimed, it being understood that the disclosure herein is merely illustrative and intended in no way in a limiting sense, changes in details of construction and arrangement of parts being permissible as long as within the spirit of the invention and the scope of the claims which follow.

In the accompanying drawings forming a part of this specification, v

Fig. 1 is a side elevational view of a comparator made according to the invention;

Fig. 2 is a fragmentary plan view, on a reduced scale, detailing features of said comparator;

I taken online 5-5 in Fig. 3;

8 Claims. (Cl. 33185) Fig. 8 is an enlarged vertical transverse sectional View, taken as on line 8-8 in Fig. 5.

A frame I!) of the comparator, adapted to be supported upon and secured to a horizontal surface, is constituted as upper, side and end walls providing a relatively shallow, rectilinear concavity II at one end of said frame and a comparatively deep, rectilinear concavity l2 at the opposite end of the frame contiguous with the concavity H. The concavities II and 12 are in alined relation in direction longitudinally of the frame In, and, in the disclosure as made,said frame is open at its lower portion.

A horizontally disposed actuator member I3 is situated in an upper portion of the concavity H and projects into an intermediate part of a portion of said concavity l2 adjacent said concavity H, and said actuator member I3 is supported by the frame it for limited-resilient movement longitudinally of said frame.

Resilient and flexible elements supporting the actuator member [3 are constituted as thin, flat plates, each denoted I4, at opposite ends of said actuator member. The thin, flat plates l4, 14 extend transversely of the frame l0 and lower marginal portions thereof are rigidly secured, as at l5, to said frame between transversely extending blocks, each indicated I6, adjacent a lower portion of the frame. The opposite ends of the actuator member l3-are secured, as at H, to upper marginal portions of. the thin, flat plates l4, 14 through the instrumentality of transversely extending blocks, each indicated l8, between which said upper marginal portions of said thin, flat plates are situated. The construction and arrangement are such that said actuator member is mounted within the frame [0 for limited, resilient, to and fro movement longitudinally of said frame while the actuator member is disposed substantially in a horizontal plane.

The actuator member I3 is constituted as an elongated platform or table which supports a horizontally disposed, elongated actuator element l9 in such manner that said actuator element is capable of adjustment longitudinally of said actuator member, as well as longitudinally of the frame 10. As shown, an upper portion of the actuator member [3 is constructed to provide. a

horizontal, longitudinally extending guideway 20 in which the actuator element i9 is slidably arthrough an opening 26 in the; end wall of the;

frame It opposite the concavity |2;. also is in:-

tegral with large and small manipulating. knobs,

represented 21 and 28, respectively, situated ex,- teriorly of said frame. A reduced portion 29, connecting the externally threaded rod; 2| with. the head 25, passesthrough and is rotatably supported by the transversely extending blocks |8, I8 and the thin, flat plate l4 at the corresponding; end of the frame, and lock nuts 30, at the interior side of and engaged with the block l8 which is adjacent said. lock nuts, retains the interior end of the head 25 engaged with the block |8 which is adjacent said head thus to preclude longitudinal movement of said externally threaded-rod. 2| relative to the actuator member l3. It will be apparent that the actuator element |9 can be adjusted longitudinally of said actuator member |3 by rotative movement of either of the manipulating knobs. The small manipulating knob 28 of course is more suitable for use to the accomplishment of quick adjustment of said actuator element, and the large manipulating knob 21 is more appropriate for use when the actuator element is to be accurately adjusted. Also it will beapparent that the frame l8 will offer no interference, to longitudinal movement of the head 25, together with the actuator member I3 and the actuator element l9 as a unit, inasmuch as said head 25is in clearing, relation to the opening 26.

The actuator element I9 is constituted as an elongated platform or tablewhich supports a vertically disposed actuator 3| in such manner that said actuator is capable of adjustment relative to said, actuator element in several different directions to, the. accomplishment of a purpose or result as. hereinafter to. be set forth.

The actuator 3|, while rigid with, the actuator element 9. is adapted to. be moved longitudinally of: the frame I0, towardthe left in Figs. 1, 3 and of the drawings, thus to causev said actuator element. l9 and the actuator member l3. to. be moved longitudinally in. the same direction, against resilient action of the thin, flatv plates l4, and in turn cause a measuring andv denoting instrument 32 of the comparator to be operated.

An indicating element 33, of inverted U-shape as shown, is fixedly supported, as at 34, on a hori zontally disposed, transversely extending shaft 35 situated in a lower portion of the. concavity l2 andv having its oppositeend portionsv rotatably mounted, as at 36, 36, in the side walls of, the frame Ill. Spaced apart legs of the U-shape indicating element 33 are disposed at opposite sides of an arc shape dial 3'! supported by said frame HI, and the base of the U of said indicating element is situated above said dial to be movable thereover beneath a transparent cover 38. The upper surface of the dial 3'! is calibrated, a indicated at 39,. o. denote small fractions of an inch, as, for example, one-thousandthsof. an

inch, or other desired measurement. As disclosed, zero on the dial is situated at its midlength between positive indications at the left and negative indications at the right. A coil spring 40, within the concavity I2 and surrounding the shaft 35, is for normally retaining the indicatingelement 33 situated, .about as in Figs. 3 and 5, to indicatea negative calibration A spool 4|, fixed on the transverse shaft 35 at a location between the legs of the U-shape indicating element 33, is adapted to be rotated against resilient action of the coil spring 40 to cause said indicating element to be moved relative to the dial 31, toward the. left in Figs. 3 and 5, in direction. away from the negative toward the positive calibrations. onsaid dial.

A horizontal actuator bar 42, for imparting rotative movement to the spool 4|, in counterclockwise direction as shown, includes a rearward end portion situated directly beneath said spool connected therewith by a ribbon or flexible strap 43 which extends upwardly from the adjacent end of said actuator bar along the side of the spool which is opposite the concavity thence along the upper side of said spool and thence along an upper part of the side of the spool which is adjacent said concavity The end of the ribbon or flexible strap 43 adjacent the actuator bar 42 is secured thereto as at 44, and the opposite end of said ribbon or flexible strap is secured as at 45 to the spool 4|. The construction and arrangement are such that longitudinal movement imparted to the horizontal actuator bar 42 in direction toward the concavity to the right in Fig. 5 of the drawings, will cause the indicating element 33 to be swung in direction away from saidooncavity H, to the left in said Fig. 5, against resilient action of the coil spring 46, and also such that said coil spring will return said indicating element to its normal position, as in Figs. 3 and 5, upon release of said actuator bar.

The actuator bar 42 extends forwardly longitudinally of the frame I8, and a forward end portion of said actuator bar projects into a lower part of the adjacent portion of the concavity beneath a rearward end portion of the actuator member l3. A lower central portion of the thin, flat plate H5 at the rearward end of said actuator member I3 is cut away to be in clearing relation to the, actuator bar.

The forward end portion of the actuator bar 42, or end portion of said actuatorbar spaced from the spool 4|, rigidly supports a crosshead 46 itself supporting spaced apart upstanding-pins, represented 41, 47, in alined relation in direction transversely of the frame It) and also supporting an upstanding pin 48 between and equally spaced from and situated slightly to the rear of the upstanding pins 47, 47. As shown, the upstanding pins 41, 48, 4'1 are in perpendicular relation to the actuator bar 42 and its crosshead 43, and each of said upstanding pins includes a horizontally disposed V-notch 49 situated in spaced relation to the crosshead. The V-notches 49 extend throughout the full circumferences of the upstanding pins, the V-notches in the upstanding pins 47, 4'! are in horizontal alinement, and the V-notch in the upstanding pins 48 is at elevation above that of said V-notches in said upstanding pins 41, 47. The V-notches provide, together with reduced portions of the upstanding pins which said V-notches produce, pivotal supports for a purpose to be made plain.

A horizontal lower pivot blade 58, at the rear of the upstanding pins" 4-1; 41' andadjustably,

rigidly supported, as at 51, in any suitable and convenient manner upon a fixed part of the frame l0, includes a transversely extending knife edge 52 engaged in the V-notches 49 of said upstanding pins 41, 41 and an intermediate portion of said knife edge 52 is cut away, as at 53, to be in clearing relation to the upstanding pin 48;

The upstanding pins 41, 48, 41, rigid with the crosshead 46, together constitute a structure having an intermediate portion thereof mounted upon the pivot blade 59 and'first and second end portions thereof disposed at opposite sides of said pivot blade.

A horizontal upper pivot blade 54, at the front of the upstanding pin 48 and supported in a manner to be described, includes a transversely extending knife edge 55 engaged in the V-notch '49 of said upstanding pin 48 at a side thereof directly opposite the knife edge 52.

The horizontal upper pivot blade 54 is rigidly supported by a horizontal retainer 56 which in the present disclosure is constituted as a strap of rigid metal bent upon itself. The transversely extending knife edge 55 projects beyond the rear end of the retainer 58, and the front end of said retainer includes a transeverse wall 51, in spaced relation to said upper pivot blade 54, having an opening therethrough. The retainer 55 extends forwardly from the pivot blade 54 which it supports in alined relation to said pivot blade in direction longitudinally of the frame 15, and the actuator bar 42 is parallel with said retainer in direction longitudinally of said frame.

The horizontal retainer 55 is secured to the actuator member [3 through the medium of a nut 58 rigid with and extending downwardly from a lower surface of said actuator member. A horizontal adjusting screw 59, disposed forwardly of and in longitudinally alined relation with said retainer 56, includes an external thread engaged with an internal thread of the nut 58, a reduced shank 60 extending rearwardly from the rearward end of said adjusting screw passed rearwardly through the opening in the transverse wall 51 of the retainer 55, a head 5| rigid with said shank and disposed within said retainer, between the pivot blade 54 and said transverse wall 51, connects the shank and the retainer to each other, and a compression coil spring 52 upon said shank and between the transverse wall 51 and the rearward end of said adjusting screw 59 normally retains said transverse wall in engaged relation with the head Bl thus to retain said head in spaced relation to the pivot blade 54. Small holes in the adjusting screw 59, for receiving a wrench, are denoted 53, and a locking screw 54 in the nut 58 is for fastening said adjusting screw 59 in set position. The adjustable connection between the nut 58 and the pivot blade 54 is included to the end that said pivot blade can be set at intended and proper relation to the pivot pin 48, and the resilient connection between said nut and said pivot blade 54, provided by the compression coil spring 62 in cooperation with other elements, is included with the end in view of protecting delicate elements of the measuring and denoting instrument 32. The compression coil spring 62 will be constructed to have strength sufiicient to transmit, without collapsing, force steadily applied to the nut 58 to cause the pivot blade 54 to be ac- Stated otherwise, the compression coil spring 62 will become collapsed, by reason of inertia of parts of the instrument 32 to be operated, in response to force violently applied to the nut 58, thus to protect said instrument parts from damage.

The pivot blade 54 will be moved to the left in Fig. 5, in response to movement of the actuator 3| toward the left, through the medium of the actuator element IS, the actuator member I3, the nut 58,-the adjusting screw 59, the compression coil spring 62 and the retainer 56. Movement toward the left of said actuator member l3 will be opposed by the resilient and flexible elements [4, l4, and upon release of said actuator 3|, said resilient and flexible elements will return the actuator member, together with the pivot blade 54 as a unit, to its normal position, thus to permit the coil spring 40 to returnthe indicating element 33 to its normal position. Movement of the pivot blade 54 in direction toward the concavity l2, to the left in Fig. 5, will cause the upstanding pin 48 to be moved in the same direction, the movement applied to said upstanding pin 48 will cause the upstanding pins 41, 41 to be swung in corresponding direction, and swinging movement of said upstanding pins 41, 41, of course upon the transversely extending knife edge 52 as an axis, will cause the actuator bar 42 to be moved in direction toward the concavity H, to the right in Fig. 5. Upon release of said pivot blade 54, the upstanding pins 41, 48, 41 will assume their normal positions, about as disclosed in said Fig. 5.

The comparator incorporates a construction and arrangement, including the vertically disposed actuator 31 as part thereof for selectively receiving a shaft, such as a wrist pin, denoted 65 in Fig. l, or a boring bar with cutting tool, represented 66 in Figs. 1 and 2, adapted to be operative in conjunction with the measuring and denoting instrument 32 to the end that said cutting tool can be accurately set in said boring bar so that the boring bar with cutting tool can have overall radius precisely the same as that of said shaft, or can have radius greater or less than that of the shaft, as may be predetermined. Stated more broadly, the comparator is capable of employment for the purpose of setting a cutting tool in a boring bar to have overall radius bearing direct relation to the radius of a shaft, either equal to, or greater than or less than the shaft radius, regardless of the cross sectional dimension of said shaft.

lhe upper wall of the frame 18 integrally or rigidly supports upstanding pieces, indicated 61 and 58, respectively, which provide spaced apart, obliquely disposed engaging surfaces, re resented 69 and 19, respectively, which face and extend downwardly toward each other. All of the engaging surfaces 59 and 19 are at the same angular relation to a vertical plane passed transversely through the frame 10 at a location between lower end portions of said engaging surfaces 59 and 10, and all of the engaging surfaces 59 are in a single plane extending transversely of said frame, as are also all of the engaging surfaces 10. And, too, the vertically disposed actuator 9| is disposed at the side of lower portions of the oblique engaging surfaces 59 and 15 adjacent to the concavity I2, as well as in adjacent relation to said lower portions of said engaging surfaces. As shown, the vertically disposed actuator 3| is situated at the transverse center of the frame I!) and there are engaging surfaces 59 and 10 at either side of said vertically disposedv actuator.

That isto say, there are. two: engaging? surfaces 69: and two. engaging surfaces at each of; the opposite sides of the vertically, disposed actuator. 31- in the disclosure asmade. The engaging surfaces 69 and 16, respectively, are at anangular relation to each other of about90 degrees. This need not, however, be the case. Allthat is necessary is that the oppositely disposedengagingsurfaces extend downwardly: toward each other: at equal angle'to a plane passed transversely through the frame H3 in perpendicular relation to its 1on7- gitudinal axis, and that all of the engagingsurfaces of each set lie in a single plane.

The oppositely: disposed engaging surfaces 69 andare-for supporting a shaft in themanner the shaft 65', disclosed in dotted. lines in Fig. 1', is-supp orted. That is, a shaft with reference to which a boring bar with cutting tool, such asBE;

is tobe set, as well as the borin bar, is supported upon the engaging surfaces 69 and if! in such manner that oppositely disposed parts of the cylinclrical surface of said shaft and said boring bar engage all of said engaging surfaces 69 and ill in the accomplishment of operation of the comparator in practice. It will be manifest that aplane passed longitudinally and diametrically through a shaft or boring bar so supported upon the engaging surfaces '69 and I9 and also passed through the frame IB in perpendicular relation to itslongitudinal axis will always be equidistantly spaced from the engagin surfaces 62 and 70, respectively, as well as at equal angle to said engaging surfaces, regardless of the actual diameter of; said shaft or boring bar. lhus, the exact center of ashaft or boring bar supported by the engaging-surfaces S9 and 'lfl'will in each instance, independently of the diameter of the shaft or boring bar, be situatedin a plane at fixed distance from and bearing precisely the same relation to each of the sets of engag n 'surface 69 and 1c, athigher, elevation in said plane in the instance of larger shafts and boring bars, and vice versa, and, obviously, since the sets of engaging surfaces 69, and 16' will locate the exact centers of shafts and boringbars of variable sizessupported thereon, throughout the full length of the shafts, in a singleplane passed transversely through the frame la in perpendicular relation to its longitudinal axis, said sets of engaging surfaces will also, bodily locate each supported shaft or boring bar. sothat it bears the same relation, except for 'size, to said mentioned single plane as. does every other supported shaft.

The vertically disposed actuator 3| includes. a vertically disposed engaging surface H which faces toward the engaging surfaces filand 1c, and

said vertically disposed. actuator is. adjustable upon the actuator element IE to the end that said engaging surface H canbe set in a vertical plane disposed transversely of the. longitudinal axis of the frame I 6.

As shown, an oblique screw 12 provides pivotal support for the actuator 31 upon the actuator element [9, a vertical screw 13 constitutes means for tilting said actuator in. a vertical plane extending longitudinally of the frame If), and aconnection Mbetween the actuator 3| and the actuator element [9 is provision for. rotational adjustment of said actuator upon said actuator element.

It might be remarked that the comparator operates on the principle of measuring a radius andreading a diameter, and the measuring operation is performed by reference to the engaging surface H which is always disposed in a plane parallel with a, plane passed longitudinally and diametrically through a supported. shaft or. boring bar transversely of theframe It) in perpendicular relation to it longitudinal axis.

In practical operation of the comparator, a shaft such as 65 the: radius of which is to be measured first will be supported upon the sets ofengaging surfaces69 and 10, and the actuator element, l9 will be adjusted longitudinally of the actuator member l3 to cause the vertical engaging surface, H to be situated at such relation to said engagin surfaces 69 and 10 that the indicating element 33 will be situated at zero calibration with said vertical engaging surface H engaged against said shaft. Then a boring bar with cutting tool, such as 66, will besupported upon said sets of engaging surfaces. 69 and 10,,and, finally, the cutting tool will be adjusted in the boring bar to cause the end of its workin end portion to force the. engaging surface H to position situating said indicating element 33 at zero calibration when said cutting tool is to produce an internal bearing surface of precisely the dimension of the shaftwhich was measured, or at. a positive. calibration when the fit of said shaft in its bearing is to be loose, or ata negative calibration when the fit of the shaft is to be tight. Of course, the vertically disposed actuator 3| and the parts which it operates will return to their normal positions upon each removal of a shaftor a boring bar from. theapparatus.

An operating tool '15,.disclosed in Figs. 1. and 2, conveniently may be employed to accomplish longitudinal adjustment of the. cutting. tool. in direction toward the verticalengaging surface H, and a, locking screw '16, or some other suitable device, maybe utilized to fasten said cutting tool in adjusted position.

Of course, the cutting tool will extend diametrically through the boring bar, and, as shown in Figs. 1 and 2, said cutting tool will be horizontally disposed during its adjustment.

It will be plain that. inasmuch as the shaft and the boring bar are centered in the same vertical. plane, parallel with the plane of. the: vertical engaging: surface 11', the overall radius of a. boring bar with cutting tool will be precisely the same as the radius of a shaftwith reference to whichthe cutting tool. is. being set when the boring bar with cutting tool situatesthe indicating element 33: at the same location on the dialas does the shaft, as well as greater than the radius of said shaftto. the. extent. denoted by said indicating element when said boring bar with cutting: tool situates the indicating element at a positive calibration on said dial and less than the; radius of'the shaft to the extent denoted by said: indicating element when theboring barwith cutting tool situates the indicating element at a negative calibration on the dial. In the instance of both a shaft and a boring bar with cutting-tool to be set by comparison with'or reference to said shaft;. the distance between parallel planes, the one including the exact center of the shaft or boringbar, as the case maybe, and the otherineludingthe vertical engaging surface, is a measurement. whichv constitutes, atone and the same time, the radius of. said: shaft and the overall radius; of said boring bar with cutting-tool. When said mentioned distance is made the same for both. the shaft and. the boring bar with cutting tool, their radii, and hence their diameters, will be. identical. When the. mentioned distance. is made greater for the boring bar with cutting tool thansfor the shaftptheiradius ofthe formerwill be greater in proportion as the distance is made greater, and when said mentioned distance is made less for said boring bar with cutting tool than for said shaft, the radius of the former will be less in proportion as the distance is made less.

What is claimed is:

1. In an apparatus for employment to set a cutting tool in. a boring bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a device for selectively seating said shaft or said boring bar, of a movable actuator adjacent said device to be selectively engaged by said shaft while seated in said device or by said cutting tool while said boring bar is seated in said device thus to be moved way from the device, means for resiliently urging said actuator toward said device, an instrumentality operable in response to movement of I said actuator away from said device against force of said means to measure and denote the radius of said shaft and the overall radius of said boring bar with cutting tool the one with respect to the other, a frame, a pivotal support upon said frame, a structure having an intermediate portion thereof mounted upon and first and second end portions thereof disposed at opposite sides of said pivotal support, a first operative connection between said mean and said first end portion, and a second operative connection between said instrumentality and said second end portion.

2. In an apparatus for employment to set a cutting tool in a boring bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a device for selectively seating said shaft or said boring bar, of a movable actuator adjacent said device to be selectively engaged by said shaft while seated in said device or by said cutting tool while said boring bar is seated in the device, first means for resiliently urging said actuator toward said device, an instrumentality operable in response to movement of said actuator away from said device against force of said first means to measure and denote the radius of said shaft and the overall radius of said boring bar with cutting tool the one with respect to the other, a frame, a pivotal support upon said frame, a structure having an intermediate portion thereof mountedupon and first and second end portions thereof disposed at opposite sides of said pivotal support, second means for accomplishing adjustment of said actuator relative to said instrumentality and toward and away from said device, a first operative connection between said first means and said first end portion, and a second operative connection between said instrumentality and said second end portion.

3. In an apparatus for employment to set a cutting tool in a boring bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a device for selectively seating said shaft or said boring bar, of a movable actuator adjacent said device with which either said shaft while seated in said device or said cutting tool while said boring bar is seated in said device is adapted to be engaged thus to cause said actuator to be moved away from the device, means for resiliently urging said actuator toward said device constituted as resilient and flexible members supporting the actuator for limited movement in direction transversely of said shaft and said boring bar while seated in said device, an instrumentality operable in response to movement of said actuator away from said device against force of said means to measure and denote the radius of said shaft and the overall radius of said boring bar with cutting tool the one with respect to the other, a frame, a pivotal support upon said frame, a structure having an intermediate portion thereof mounted upon and first and second end portions thereof disposed at opposite sides of said pivotal support, a first op-' erative connection between said means and said first end portion, and a second operative connec-, tion between said instrumentality and said sec-; ond end portion.

4. In an apparatus for employment to set a cutting tool in a boring bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a device for selectively seating said shaft or said boring bar, of a movable actuator adjacent said device withwhich either said shaft while seated in said device or said cutting tool while said boring bar is seated in said device is adapted to be engaged thus to cause said actuator to be moved away from the device, first means for resiliently urging said actuator toward said device constituted as resilient and flexible members supporting the actuator for'limited movement in direction transversely of said shaft and said boring bar when seated in said device, an instrumentality operable in response to movement of said actuator away from said de vice against force of said first means to denote the radius of said shaft and the overall radius of said boring bar with cutting tool the one with respect to the other, a frame, a pivotal support upon said frame, a structure having an intermediate portion thereof mounted upon and first and second end portions thereof disposed atop posite sides of said pivotal support, second means for accomplishing adjustment. of said actuator relative to said instrumentality and toward and away from said device, a first operative connection between said'first means and said first end portion, and a second operative connection between said instrumentality and said second end portion.

5. In an apparatus for employment to set-a cutting tool in a boring bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a device for selectively seating said shaft or said boring bar, of a movable actuator adjacent said device to be selectively engaged by said shaft while seated in said device or by said cutting tool while said boring bar is seated in said device thus to be moved away from the device, means for resiliently urging said actuator toward said device, an instrumentality, including an indicating element and a calibrated surface relative to which said indicating element is adapted to have movement, operable in response to movement of said actuator away from said device against force of said means to measure and denote the radius of said shaft and the overall radius of said boring bar with cutting tool the one with respect to the other, a frame, a pivotal support upon said frame, a structure having an intermediate portion thereof mounted upon and first and second end portions thereof disposed at opposite sides of said pivotal support, a first operative connection between said means and said first end portion, and a second operative connection between said instrumentality and said second end portion.

-6. In an apparatus for employment to set a cutting tool in a boring bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a frame and a device supported on said frame for selectively seating said v 1.1 shaftior said boringibar, of .a movable actuator adjacent said device with which either said shaft orsaid cutting tool-is adapted to be engaged thus toacausesaidactuator to be moved away from said device, .means for resiliently urging said actuator towardsaid device constituted as resilient andfiexib'le members .supporting the actuator upon said frame .for limited movement in direc- .tion transversely of said shaft and said boring bar when seated in said device, an ins'trumentality operable inresponse to movement of said actuator away fromsa'id deviceagainst force of said means to measure and denote the radius of said shaft and the overall radius of said boring bar with cutting .tool .the :one with respect to the other, .a pivotal support upon said frame, a .structureshavinganintermediate portion thereof .mounted upon vandiirst and second endportions thereof disposedat opposite sides of said pivotal support, a .firs'toperative connection between said 'meansand end portion, and a second operative connection between said Jinstrumentality-andsaidsecon'd end portion.

In an apparatus for employment to set a cutting toolin a'looring'bar to have overall radius bearing direct relation to the radius of a shaft, the combination with a frame and a device supported on said frame for selectively seating said shaftor-saidboring'bar, of an actuator member, resilient and .fiexible elements supporting the actuator memberupon the frame \for limited, resilient lmovement transversely of said device, an actuator element upon and adjustable longitudinallvof "said actuator member and adjustable transversely of said device, mechanism for accomplishing longitudinal adjustment of said actuatorelement anactuator upon said actuator element and adjacent said device with which either saidshaftlorsaid cutting tool is adapted to :be engaged thus to cause said resilient and fiexilfleelements .toibe flexed and saidia'ctuator, actuator element and actuator member to be moved-transversely of said device, said resilient and flexible elements constituting .means for 1'2 resiliently urging said actuator toward said device, an instrumentality operable in response to movement of said "actuator :away from said device against. force of said means to measure and denote the radius of said shaft and the overall radius of said boring bar with cutting tool the one with respect tothe other, a pivotal support upon said frame, a structure having an intermediate portion thereof mounted upon and first and second end portions thereof disposed at opposite sides of said pivotal support, a first operative connection between said actuator member andsaid first end portion, and a second operative connection between said instrumentality and said second end portion.

.8. The combination as specified "in claim '7 wherein said first operative connection includes a collapsible, resilient element as'part thereof.

'EWALD A. ARP.

REFERENCES CITED .The following references are of record in'the file of this patent:

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